The purpose of this multi-site study is to localize, identify, and evaluate common polymorphic variation in genes involved in determining interindividual differences in blood pressure levels and essential hypertension status in three racial groups: African-Americans, Hispanic, and non-Hispanic Whites. Subjects in this multi-site study will be recruited from three sites: African Americans from Jackson, MS; Mexican-Americans from Starr Couty, TX (Dr. Harris) and non-Hispanic Whites from the Rochester, MN population (Dr. S. Turner). Blood samples from these sites are shipped to the Mayo Immunochemical Core laboratory for analyses of insulin and lipoproteins. These measurements are supported by the Mayo GCRC grant and therefore through ancillary funds. Measurements of insulin and lipoproteins are strong correlates of blood pressure and hypertension, and will potentially provide clues to the pathway of the traits which genetic variation influences inter- individual and racial differences in blood pressure. These tests were requested in the grant application but were cut in final budget negotiations.